Linear alkylbenzene compositions



United States Patent 3,358,047 LINEAR ALKYLBENZENE COMPOSITIONS Thomas Raymond Liston, Hamburg, N.Y., assignor to Allied Chemical Corporation, New York, N.Y., a corporation of New York No Drawing. Filed Mar. 11, 1965, Ser. No. 439,057 Claims. (Cl. 260-668) ABSTRACT OF THE DISCLOSURE This invention relates to linear alkylbenzene compositions which are useful in the manufacture of alykylbenzene su'lfonate compositions readily degraded by microorganisms found in sewerage, i.e., biodegradable detergents. The alkylbenzenes of the present invention comprise mixtures of phenylalkanes in which the alkyl substituents are essentially linear ,and contain from 8 to 18 carbon atoms, the relative proportion of the 2- phenylalkane content of the lowest molecular weight phenylalkane species present in the mixture being at least 5% higher than that of the Z-phenylalkane content of the next higher molecular species, which in turn is at least 5% higher than that of the Z-phenyl content of the next higher molecular species, and preferably the overall content of 2-phenylalkanes present in the mixture of phenylalkanes being at most about 22% by weight.

This invention relates to improved linear alkylbenzene compositions More particularly it relates to linear alkylbenzene compositions which are eminently useful for production of linear alkylaryl sulfonate compositions characterized by excellent detergent properties.

The preparation of linear a'lkylbenzene compositions in which the alkyl groups are derived from mixtures of essentially straight chain hydrocarbons containing from 8 to 18 carbon atoms and which are useful in the manufacture of alkylbenzene sulfonate compositions readily degraded by microorganisms found in sewerage, i.e., biodegradable detergents has become increasingly important in view of the growing demand for such products.

Although the preparation of "linear alkylbenzenes follows closely the methods which have been developed for the preparation of the conventional branched chain alkylbenzenes, i.e., condensation of a selected mixture of alkylchlorides with benzene in the presence of aluminum or aluminum chloride as catalyst, it has been determined that the resultant linear alkylbenzene compositions contain an undesirably high content of the 2-phenylalkane isomers. Inasmuch as it is known that various 2-alkylbenzene sulfonates are inferior in detergent properties to those analogous compositions in which the point of attachment of the aryl radical is more remote from the terminal carbon of the linear carbon chain, it has been concluded that alkylbenzene sulfonate compositions, particularly those in which the alkyl chains are derived from mixtures of hydrocarbons which contain an average of more than twelve carbon atoms, should contain 20% or less of the 2-phenyl isomers in order to possess acceptable detergent properties.

Copending US. application S.N. 415,497 filed Dec. 2, 1964 includes a disclosure of a process for preparing linear alkylbenzene compositions having a desirably low content of 2-phenylalkanes by a process which includes the steps of:

(a) Condensing an n-alkylhalide with benzene in the presence of aluminum chloride.

(b) Distilling the crude condensation mass, after separation therefrom of tars, excess benzene, aliphatic hydrocarbons and the like, to recover a fraction of n- "ice alkylbenzene low in 2-phenyla1kanes and a fraction of n-alkylbenzenes high in 2-phenylalkanes; and

(0) Conversion of the low-Z-phenylalkane fraction to the corresponding alkylbenzene sulfonate detergent composition.

The above-mentioned copending application also discloses that the complexity of the fractions obtained is a function of the complexity of the hydrocarbon mixture utilized. Thus, a hydrocarbon feed stock containing about equal amounts of undecane, dodecane and tridecane could result in the production of an alkylbenzene composition of low 2-phenylalkane content which was rich in phenylundecanes but poor in phenyltridecanes. By utilizing hydrocarbon feed stocks of essentially a pure linear hydrocarbon, i.e., n-undecane, n-dodecane, etc. and processing said hydrocarbons, to essentially pure phenyl alkanes of low Zphenylalkane content in the above manner, and thereafter blending the several essentially pure phenylalkanes, it is possible to obtain an infinite number of mixtures, all having a low 2-phenylalkane content.

I have previously observed that linear alkylbenzene sulfonate detergent compositions derived from various mixtures of linear alkylbenzenes of low 2-phenylalkane content and wherein the Z-phenylalkane content of each of the molecular species present is approximately the same, vary considerably with respect to their detergent properties. (A single molecular species is understood to include one or more phenylalkanes, wherein the alkane moiety is derived from a single alkane hydrocarbon, e.g. dodecane.) I have now observed that, surprisingly, linear alkylbenzene sulfonate compositions derived from various mixtures of linear alkylbenzenes of low Z-phenylalkane content and wherein the Z-p-henylalkane content of each of the molecular species present is significantly different, do not produce the same wide variation of detergent properties as was observed previously. Thus, when the 2-phenylalkane content of each of the molecular species present in an alkylbenzene mixture is significantly dilferent, and particularly when the Z-phenylalkane content of the lower molecular weight alkylbenzene is greater than that of the higher molecular weight alkylbenzene, the degree of latitude permitted in the selection of the mixture of the molecular species to be converted to alkylbenzene sulfonates of superior detergent properties is greater than when the Z-phenylalkane content of each of the molecular species present is substantially the same.

In accordance with the present invention, there are provided new compostiions of matter com-prising mixtures of phenylalkanes in which the alkyl substituents are essentially linear and contain from 8 to 18 carbon atoms, the relative proportion by weight of the 2phenylalkane content of the lowest molecular weight phenylalkane species present in the mixture being at least 5% higher than that of the Z-phenylalkane content of the next higher molecular species which in turn is at least 5% higher than that of the 2-phenyl content of the next higher molecular species, and preferably the overall content of Z-phenylalkanes present in the mixture of phenylalkanes being at most about 22% by weight.

The products of this invention can betprepared in several ways. Preferably, separate streams of phenylalkanes, in each of which the alkyl substituent is derived from a single hydrocarbon, e.g. n-dodecane, and in which the 2-phenylalkane isomer has been adjusted to the desired level, are mixed; then, for conversion to detergent compositions, the resultant mixture of phenyl-alkanes is sulfonated, neutralized, and dried and the alkylbenzene sulfonate mixture produced is mixed with suitable builders and other conventional detergent components. Alternatively, mixtures of n-alkanes, e.g., a 20% dodecane- 80% undecane mixture or a 30% tridecane-70% tetradecane mixture, can be separately processed to low 2- phenylisomer mixtures of phenylalkanes, e.g. in the above manner, and thereafter equal parts of each of these two mixtures blended together. When processed further to alkylbenzene sulfonates they produce detergent composition of superior detergent properties.

I have found that the latitude in formulating the alkylbenzene compositions suitable for conversion to high quality alkylbenzene sulfonate detergents is dependent to a major degree upon the spread (i.e. the relative difference) of the Zsphenylalkane content of the various phenylalkane components present in the mixture. In general, the greater the spread among the relative amounts of the several Z-phenylalkanes present, the greater will be the permissible variation of the composition with respect to the amounts of the several phenylalkanes used in the production of the detergent compositions. Preferably, the 2-phenylisomer of the lowest molecular weight isomeric group should be present in a proportion by weight with respect to its isomeric group which is at least about greater than that of the next higher member with respect to its isomeric group, which in turn should be present in a proportion which is at least about 5% higher than the next higher member with respect to its isomeric group. Highly effective mixtures of alkylbenzenes and hence especially preferred are those that contain essentially phenyldodecanes of which about 20 to about 30% by weight is the 2-phenyldodecane, phenyltridecanes of which about to about 20% by weight is Lphenyltridecane, and phenyltetradecanes of which about 5 to about 12% by weight is Z-phenyltetradecane.

The following examples will illustrate my invention. Parts and percentages are by weight and temperatures are given in degrees centigrade, unless otherwise specified. and a hydrogen flame ionization detector. The column tographically using a Model 154-D Perkin-Elmer Gas Chromatograph equipped with a Stainless Steel Golay Column, 150 ft. x 0.01 in I.D., coated with 2% squalene and a hydrogen flame ionization detetctor. The column was operated at about 140 C.

EXAMPLE 1 Part A.A mixture of phenyldodecanes containing 22% of the 2-phenylisomer and prepared from dodecyl chloride and benzene as described in copending US. application Ser. No. 415,497, filed Dec. 2, 1964, a similarly prepared mixture of phenyl tridecanes containing 2-phenyl tridecane, and a similarly prepared mixture of phenyl tetradecanes containing 8% 2-phenyl tetradecanes were blended in the following sixteen different ratios expressed in weight percent.

F. in both soft (50 Hardness) and hard (150 Hardness) water. Dinner plates, covered with a standard soil, were immersed several at a time in the detergent solution and washed by hand. The number of plates which can be washed before the disappearance of the suds from the solution is taken as a measure of the detergency of the compositions. In these tests, a minimum of 19 plates in soft Water and a total of 40 plates in soft and hard water was taken as the dividing line between high and low quality detergent compositions.

The results of this dishwashing evaluation test are reported below:

(a) Blends 1, 3, 5, 10, 11, 13, 14 and 15 produced high quality detergent mixtures.

(b) The average number of plates washed by all sixteen compositions was 19.7 in soft water and 23.4 plates in hard water.

EXAMPLE 2 The procedure of Example 1, Part A, was repeated differing in that each of the alkylbenzenes contained 20% of each of the 2-phenylalkanes. These were blended in sixteen blends having the weight distributions indicated and the blends converted to detergent compositions as indicated.

The results of the dishwashing evaluation of the sixteen detergent compositions prepared in this example follow:

(a) Only three blends produced high quality detergent compositions: blends 5, 12, and 13.

(b) The average number of plates washed by all compositions was 14.9 in soft water and 20.6 in hard water.

EXAMPLE 3 In a similar fashion, sixteen blends of alkylbenzenes consisting of mixtures of phenyldodecanes, phenyltridecanes and phenyltetradecanes were prepared in which the 2-phenyl isomer content of each of the molecular species was about 15%.

The blends were converted to detergent compositions which were evaluated as detergents by the test described above. The results follow:

(a) Only four blends of the alkylbenzenes produced high quality detergent compositions: blends 1, 3, 10, and 13.

(b) The average number of plates washed by all sixteen of these compositions was 15.0 plates in soft water and 20.9 in hard water.

EXAMPLE 4 In this example, the procedure of the above examples was followed save that the three phenylalkane species each contained 10% of the 2-phenyl isomer.

Blend 1 2 3 4 5 s 7 s 9 10 11 12 13 14 15 16 o 10 10 13 15 15 1s 20 20 25 30 30 a5 40 40 45 0 c 45 as 33 7o 50 41 35 50 40 35 30 35 20 10 3 o 45 55 54 15 35 41 20 45 25 30 35 35 25 40 45 15 Each of the above blends of phenylalkanes was con- The dish washing test conducted with the sixteen deterverted to the corresponding mixture of sodium alkylgent compositions gave the following results: benzene sulfonate in the conventional manner and each 1 of these mixtures was converted to a built detergent com- 2 9? f g g iz z f g l iq ig g 2 position having the following composition: i y g p en S an Organic sulfonates ga (b) The average number of plates washed by all sixteen S compositions was 16.5 plates in soft Water and 20,8

odium tripolyphosphate 32.4 plates in hard Water Sodium silicate 23.6 Sodium sulfate 16.7 EXAMPLE 5 Part B.The detergent compositions prepared in Part A above were evaluated as detergents on the basis of their performance in a standard dishwashing test.

In this test solutions of the detergent under test were made at 0.15% (1.62 grams/liter) concentration at 115 Part A.A mixture of normal hydrocarbons consisting of about 22% n-dodecane and about 78% n-tridecanes was converted to a low 2-phenylalkane mixture of alkylbenzenes substantially as described in copending application S.N. 415,497. This mixture contained 22% n-phenyl- Weight Percent Percent Z-phenyl Isomer Alkylbenrene:

Phenyldodecanes 13 26 Phenyltridecanes.. 54 16 Phenylt etradecanes 33 This blend of alkylbenzenes, containing about 2- phenylalkanes was converted by sulfonation, neutralization and admixture with conventional builders as indicated in Example 1 above, to a high quality detergent composition. The detergent properties of this composition were evaluated by the dishwashing test described in the above examples. This composition washed 19 plates in soft water and 22 plates in hard water, indicating that this detergent composition possessed excellent detergent properties.

It can thus be seen that a novel and effective means for preparing high quality detergent compositions has been devised, and that further by control of the Z-phenyl content of the several molecular species of the alkylbenzene mixture, considerable latitude in the formulation of the alkylbenzene mixture can be obtained.

My invention has been described and illustrated by several illustrative examples which include the best mode presently known for practicing this invention. It should be distinctly understood, however, that these purely illustrative examples are not to be interpreted in a limiting sense. Many variations in the specific details contained in these examples will be obvious to those skilled in this art, and such variations since they do not involve a departure from the scope or spirit of my invention are to be included therein.

I claim:

1. As a new composition of matter, a mixture of essentially normal phenylalkanes the n-alkyl substituents of which contain from 8 to 18 carbon atoms, and in which the proportion of the Z-phenyl isomer of each isomeric group present in significant amount is at least about 5% higher than the proportion of the 2-phenyl isomer of the next higher group, each with respect to its own isomeric group.

2. As a new composition of matter, a mixture of essentially normal phenylalkanes the n-alkyl substituents of which contain from 8 to 18 carbon atoms, and in which the proportion of the 2-phenyl isomer of each isomeric group present in significant amount is at least about 5% higher than the proportion of the 2-phenyl isomer of the next higher group, each with respect to its own isomeric group, the overall content of Z-phenylalkanes being at most about 22% by weight.

3. A mixture of linear alkylbenzenes consisting essentially of phenyldodecanes, phenyltridecanes and phenyltetradecanes, the phenyldodecanes comprising about 20 to about 30% by weight of Z-phenyldodecane, the phenyltridecanes comprising about 10 to about 20% by weight of Z-phenyltridecane, and the phenyltetradecanes comprising about 5 to about 12% by weight of Z-phenyltetradecane.

4. A mixture of linear alkylbenzenes consisting essentially of phenyldodecanes, phenyltridecanes and phenyltetradecanes, the phenyldodecanes comprising about 22% by weight of 2-phenyldodecane, the phenyltridecanes comprising about 15% by weight of 2-phenyltridecane and the phenyltetradecanes comprising about 8% by weight of Z-phenyltetradecane.

5. A mixture of linear alkylbenzenes consisting essentially of phenyldodecanes, phenyltridecanes, and phenyltetradecanes, the phenyldodecanes comprising about 26% by weight of 2-phenyldodecane, the phenyltridecanes comprising about 16% by weight of 2-phenyltridecane and the phenyltetradecanes comprising about 10% by weight of 2-phenyltetradecane, said mixture containing not over about 22% by weight of 2-phenylakane isomers.

References Cited UNITED STATES PATENTS 2/ 1964 Sharman 260-671 2/ 1966 Shannan 260*671 X OTHER REFERENCES Sweeney et al.: The Journal of the American Oil Chemists Society, December 1964, pp. 815-822. 

1. AS A NEW COMPOSITION OF MATTER, A MIXTURE OF ESSENTIALLY NORMAL PHENYLALKANES THE N-ALKYL SUBSTITUENTS OF WHICH CONTAIN FROM 8 TO 18 CARBON ATOMS, AND IN WHICH THE PROPORTION OF THE 2-PHENYL ISOMER OF EACH ISOMERIC GROUP PRESENT IN SIGNIFICANT AMOUNT IS AT LEAST ABOUT 5% HIGHER THAN THE PROPORTION OF THE 2-PHENYL ISOMER OF THE NEXT HIGHER GROUP, EACH WITH RESPECT TO ITS OWN ISOMERIC GROUP. 